First- and Second-Generation Antihistamines

Description

Allergic rhinitis (AR) and urticaria are among the most common allergic conditions pharmacists encounter, with symptoms often impairing sleep, concentration, and quality of life. Histamine is the key mediator driving these conditions, making H1 antihistamines the cornerstone of therapy. This CPD activity reviews the pathophysiology of AR and urticaria, and compares the pharmacological properties of first- and second-generation oral antihistamines. Special emphasis is placed on lipophilicity, blood–brain barrier penetration, and their effects on the central nervous system. Pharmacists will learn to differentiate between sedating and non-sedating options, counsel on safe and effective choices such as fexofenadine and bilastine, and consider interactions with food and lifestyle factors when advising patients.

Learning Objectives

After completing this activity, pharmacist should be able to:

• discuss the pathophysiology of allergic rhinitis and urticaria;
• outline the oral pharmacological treatments for allergic rhinitis;
• discuss the difference between the first and second generation of antihistamines with respect to their lipophilicity and their ability to penetrate the blood–brain barrier;
• understand which oral antihistamines have approximately 0% brain occupancy or modest brain occupancy and brain interference.

Expires 31st December 2025